I am again running El Capitan on my MacBook after having the computer sent in last week and the mainboard replaced. Shortly after updating to the official release version my MacBook crashed and was giving me a hard time logging in - very similar to the issues I was having with the GM. I tried to restore to Yosemite from a backup or from a clean usb install and was unable to so the machine was sent in and the logic board was replaced. I received it back with a clean Yosemite install which I wiped and then installed El Capitan clean.
So far things seem good. The best news is that battery life now appears on par with what I was getting with Yosemite, and of course, all animations and Safari scrolling is MUCH smoother. It's unfortunate that this hardware failure coincided with my installation of Beta software because it sure made diagnosing what was going on difficult!